Ransomware attack removal guide
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| Ransomware attack |
What is ransomware?
Ransomware is a type of malware encrypts victims files and demand a ransom to decrypt them, it adds a new extension to mark the encrypted files.
Ransomware attack
Have you ever wondered what is causing all the hype around harmful ransomware? I heard about it in the office or read about it on the news. You might now see a message on your computer screen warning you about a ransomware virus. Well, if you are interested in knowing all the ransomware-related information, you've come to the right place. We'll tell you about the different types of ransomware, how they infect your device, where they come from, who they're targeted for, and what actions you need to do to protect your device from them.
What is a harmful ransomware virus
Ransomware, is a type of malware that prevents users from accessing their systems or their personal files and requires a ransom to be paid to regain access. The first types of ransomware appeared in the late 1980s, with ransomware sent via traditional mail. Today, ransomware attackers require that you send money in cryptocurrency or credit card.
How does ransomware work
There are a variety of ways in which ransomware can harm your computer. One of the most prevalent methods today is malicious spam, or mail spam, which is unsolicited mail used to send malware. The email may contain phishing attachments, such as PDFs or Word documents. It may also include links that direct you to malicious websites.
Malicious spam uses social engineering to trick people into opening attachments or clicking on links that appear as legal attachments or links, whether that appears to be from a trusted organization or a friend. Cyber criminals use social engineering in other types of malicious ransomware attacks, such as impersonating an FBI member to install fear in users and force them to pay a sum of money to unlock their files.
Another common and used method of doing harm, which reached its peak in 2016, is malicious advertising. Malicious advertising or malicious advertising, consisting of the use of online ads to distribute malicious software, with or without the user being partially or not. While browsing websites, and even healthy websites, users can be directed to criminal servers without clicking on an ad. The servers collect these details about the victim's computer and its location, and then determine the type of malware appropriate to send. Often, what this malicious program is is a harmful ransomware.
Malicious ads often use a malicious embedded frame, or invisible web page element, in order to do their job. The embedded framework redirects to a disabled virus' mobile page, and a malicious code attacks the system from a mobile page via a set of disrupted viruses. It all happens without the user's knowledge, which is often referred to as drive-by-download.
Ransomware Types
There are three main types of harmful ransomware, ranging in severity from medium annoyance to the serious Cuban missile crisis. It is as follows:
- Scareware
Scary programs, it turns out, are not scary. These include fraudulent security software and technical support messages. You may receive a pop-up message claiming that a malware has been detected and there is no way to get rid of it except by paying a sum of money. And if you do nothing, the popup messages may still be sent to you, but your files remain completely safe.
A proper cybersecurity program will not require customers to pay anything this way. If you don't already have this company program on your device, the program will not monitor your computer for ransomware viruses. If you have security software installed on your device, you will not have to pay any money to remove this virus because you have already paid for the program in order for it to perform that task perfectly.
- Screen lockers
Update to the orange alert for these criminals. When your computer is exposed to harmful ransomware using the lock screen, this means that you will not be able to use your computer completely. Once your computer is up and running, a full-size screen will appear, often accompanied by an official-looking FBI or Department of Justice stamp, that screen alleges that illegal activity has been detected on your computer and you have to bay some money as a ransom. However, the FBI will not stop you from using your computer or require you to pay money for any illegal activity. If the FBI suspects that you are engaged in piracy or exploiting children in pornography or other cyber crimes, it will comply with the relevant legal channels.
- Encrypting ransomware
This type is very frightening. These are the attackers who steal and encrypt your files, and then demand that you pay money to decrypt and resend them. The reason this kind of malicious ransomware is so dangerous is that cyber criminals steal your files, and there are no security software or system restore software that can get them back for you. If you do not pay the ransom, you will likely not get it again. And even if you pay the ransom, there is no guarantee that cyber criminals will get those files back for you.
What can ransomware do?
It marks the encrypted files By high level of encryption then adds an extension to them, each file name will be ended with two extensions, victims will not be able to access them.
For example: "video.mp4” will be named as “video.mp4.xxxx”, and also it will put text document (_readme.txt) inside each encrypted folder.
A unique decryption key and it is different for each infected computer system.
This needed decryption key is hosted on a server under the criminals full control, who have actually loaded the ransomware into the internet each victim will have unique id, the victim told to contact the attackers to pay the ransom.
There is no warranty that these online Cyber-criminals will keep their promises, so you may lose your money for nothing.
How ransomware attacks files?
They use many tricks to phish their victim: By spam e-mails, Some Fake Ads on free hosting websites, Some unsafe torrent software, or Opening these types or clicking on the harmful links might harm the system.
How To protect from the virus Cyber-attack?
You'll be safe if you: Do not open any e-mail attachments, specifically from unknown sender, Do not install unsafe freeware, Install an antivirus with last update, to check each file before opening it.
How to remove ransomware?
We made a guide for windows 10 users to remove ransomware and it is available on Mango school channel.
Recommendation:
You have to change all your passwords used on the infected device because the ransomware may steal the passwords stored in your browser and send them to the gangs.
How to decrypt encrypted files ?
for big size files: remove the newly added extension. this method depends on virus ability of reading and encrypting the file, so it will not add the file marker. incase each file is larger than 2GB. Please, leave a comment if that will work for you.
STOP/Djvu variants:
Make sure to launch the Emsisoft tool as an administrator. then agree with the license terms by clicking on "yes" button.
The tool will automatically find the available drives, including any connected drives, and for more locations can be selected with the “Add” button.
After adding the needed locations for decryption into the list, click on the “Decrypt” button to start the decryption procedure.
The main screen may turn you to a status view, letting you know of the active process and the decryption statistics of your data.
The tool will notify you at the end of the decryption process.
Emsisoft tool might display different messages while decrypting files:
- No key for New Variant online ID | so, the decryption is impossible.
Your original files were encrypted with an online key you run the virus while you are connected to the internet. So no one has the same encryption/decryption key pair.
If the malware is able to connect with its control servers then it will obtain and use a unique randomly generated ONLINE KEY which will allow it to keep encrypting files with that key from memory, Without the master private RSA key that can be used to decrypt your files, decryption is impossible...the key is generated in a secure way that cannot be brute-forced. The public RSA key alone that encrypted the files is useless for decryption, therefore a malware sample of any particular variant is also useless for decryption since it only contains the public key.
- No key for new variant offline ID | so, Decryption may be possible in the future.
Receiving this message is good news for you, because it might be possible to restore your files in the future, follow updates regarding the decryptable DJVU versions.
If the malware is unable to connect with its servers and fails to get an ONLINE KEY it will give up and resort to using an OFFLINE KEY. The OFFLINE KEY is a hard-coded built-in encryption KEY (used with a built-in OFFLINE ID) at the time the ransomware encrypted your files. Each variant extension only has one OFFLINE ID (a string of numbers and letters that identifies the infected computer to the ransomware) which generally ends in "t1" so they are usually easy to identify.
- Remote name could not be resolved | It refers to DNS problem on your PC, so reset your HOSTS file back to default.
What's hosts file?
How to Fix Empty Hosts File?
- Press the Windows key.
- Type Notepad in the search field.
- In the search results, right-click Notepad and select Run as administrator.
- From Notepad, open the following file as a text file: c:\Windows\System32\Drivers\etc\hosts.
- Make the necessary changes to the file if it's empty copy and past the next into the opened file according to your windows.
- Select File > Save to save your changes.
- More solutions| backup/save your encrypted files and wait for a possible future solution.
No person can change the encryption from online to offline.
Extension appended to the end of the encrypted data filename
1- Older STOP (Djvu) Ransomware encryptions before August 2019
2- Newer STOP (Djvu) Ransomware Extensions after august 2019
Incase there is NO connection between victims and encryption server
If the malware is unable to connect with its servers and fails to get an ONLINE KEY it will give up and resort to using an OFFLINE KEY. The OFFLINE KEY is a hard-coded built-in encryption KEY (used with a built-in OFFLINE ID) at the time the ransomware encrypted your files. Each variant extension only has one OFFLINE ID (a string of numbers and letters that identifies the infected computer to the ransomware) which generally ends in "t1" so they are usually easy to identify.
Incase there is a connection between victims and encryption server
If the malware is able to connect with its control servers then it will obtain and use a unique randomly generated ONLINE KEY which will allow it to keep encrypting files with that key from memory, Without the master private RSA key that can be used to decrypt your files, decryption is impossible...the key is generated in a secure way that cannot be brute-forced. The public RSA key alone that encrypted the files is useless for decryption, therefore a malware sample of any particular variant is also useless for decryption since it only contains the public key.
Remove Ransomware Manually
Ransomware that can get infected no matter how careful you are. Ransomware is often a problem overseas. It is actually very difficult to completely remove infected ransomware. However, in some cases you can recover your data with minimal ransomware impact. Let's introduce how to do this this time.
Method 1. Use Ransomware analysis tool
There are many different types of ransomware found in the world, and some types may or may not be able to restore files. If your security company has an analysis tool for known ransomware, you can use it to get your files back without paying a ransom.
The existence of analysis tools starts with knowing the type of ransomware. A website called "ID Ransomware" will identify the type of ransomware by submitting a sample file that has been damaged by ransomware. The presence or absence of the unlocking tool is also posted, so if you get infected, please use it. For new ransomware, the unlock tool hasn't come out yet. Let's try a method other than recovery with the unlock tool.
Method 2. Revert Files from backup
If you regularly back up your data to a physical server or cloud storage, you can clean up the infected computer and then recover the data.
First, disconnect the LAN cable from the relevant computer to prevent the damage from the ransomware from spreading. For wireless, turn off Wi-Fi. After disconnecting all connections between your computer and the outside world, refresh your antivirus software's virus definition files and then scan your computer for infected files.
If you find the file, quarantine it, scan your computer, and clean it up. Restore the corrupted file from backup and you're done. At this time, if the backup data also seems to be infected with ransomware, the clean computer will be damaged by ransomware again. Make sure to check the status of the backup file before restoring the file with backup.
Method 3. Use shadow copy
If you can't recover your data using methods 1 and 2, try Shadow Copy. Shadow Copy is a backup system owned by Windows OS that allows you to make copies of corrupted files. If you haven't backed up to another hard disk or cloud storage, back it up in advance.
Shadow copies are stored in the VSS file, but the problem is if the ransomware has deleted the VSS file. Unfortunately, shadow copy cannot be used at this time. Please note that because ransomware has evolved to a high degree, there are many cases where shadow copy does not work.
There is a ransom request screen on your computer … What would you do?
What do you think you would do if you suddenly see a ransom request screen that you don't remember while using your computer? We conducted a questionnaire to 100 men and women.
Do you take measures against ransomware or ignore them?
・ Ignore the ransom request. And if you can't turn off the screen, return it to the state it was in when you bought your computer. (50s / part-time job / female)
・ If it is a company computer, immediately disconnect the LAN cable and contact your superior and information system department. Then, we will deal with it while receiving instructions. (40s / Permanent Employee / Male)
・ If the ransom request screen suddenly appears on your computer, restore the system. (30s / permanent employee / male)
・ I think you will be surprised. Don't touch it badly until you talk to someone who is familiar with it. (40s / manager / male)
・ I'm surprised, but I ignore it because I think it's ransomware. (40s / Permanent Employee / Female)
Many people who didn't realize that it was a ransomware demand for ransomware seemed to say "ignore". However, some respondents said they would ignore it because it was ransomware, so it was clear that many people did not have detailed knowledge of ransomware.
Isn't it possible to remove ransomware and recover data 100%?
Overseas, there are cases where the decryption key was obtained in response to a ransom request and the in-house data was recovered. However, it does not always give you the decryption key. If you are forced to pay the ransom with company data as a shield, it is not a good idea to pay it easily. Ransom payment is a last resort. It is very difficult to get rid of infected ransomware, and it is very important to take measures at the water's edge to prevent infection and to perform regular backup work in case of infection.
Some ransomware developers have stopped expanding ransomware and released their decryption keys. However, you can think of this as a fairly rare case. Especially in the case of new types of ransomware, it may not be possible to recover and it may be in a state of being overwhelmed. The more data and endpoints your enterprise uses, the more costly and time-consuming it will be to recover. Keeping in mind that your computer will not be infected with ransomware, I always want to be careful when doing business.
Summary
There are only two ways to get rid of ransomware that has invaded your computer: pay the ransom to get the decryption key, or wait for the developer to release the decryption key. However, the method is quite uncertain, provided that both are sure to get the key. Keep in mind that ransomware is the best way to prevent it.
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